docs: clarify when to use update_todo_list tool

src/core/prompts/tools/update-todo-list.ts

@@ -56,7 +56,7 @@ Replace the entire TODO list with an updated checklist reflecting the current st
 </update_todo_list>
 
 **When to Use:**
-- The task involves multiple steps or requires ongoing tracking.
+- The task is complicated or involves multiple steps or requires ongoing tracking.
 - You need to update the status of several todos at once.
 - New actionable items are discovered during task execution.
 - The user requests a todo list or provides multiple tasks.